A picture filling the back page of the newspaper Space News displays the most powerful rockets in the Soviet armada.

At one time the picture, if it had appeared at all, might have seemed an arrogant threat of Soviet might. But in these days of glasnost and perestroika it's an advertisement soliciting space business, much as Ford prints ads to sell cars."Need a Ride?" is the come-on.

The Soviet rockets stand as if for a family portrait. They range from the slender Kosmos and the workhorse Soyuz, to the Energiya, the most powerful launch vehicle in the world. Its carrying power rivals the mighty Saturn that propelled U.S. astronauts to the moon. It will be used for the Soviet space shuttle, Buran.

The ad was placed by the Space Commerce Corp., a Houston firm that has American marketing rights for Soviet rockets. The sales effort comes at a time of a sharp drop in space launches by the cash-poor Soviets.

Art Dula, president of Space Commerce, said in a telephone interview Tuesday that he placed the ad because Space News' Jan. 21 issue spotlighted launch vehicles. The advertisement is a painting made in Leningrad by artist Sasha Timofev.

Dula said his company has had moderate success attracting customers to the Soviet rocket fleet.